Cylinder head

“ The cylinders may be detached and changed if required, one size of bed answering for three different sizes of cylinder, which may vary only in diameter, the stroke being the same, so that the castings for engines of different power are the same except in the matter of the cylinders and pistons, and all the parts are interchangeable—a feature of modern engine building that cannot be too highly valued. ”

“ How to find which Cylinder Misses.—Endeavour first to ascertain which cylinder is the culprit. One method of doing this is to place your hand on each exhaust pipe while the engine is running. You will then get a bad burn from every one except that belonging to the faulty cylinder. A more convenient way—if electric ignition is fitted—is to stop the working of three out of four of the induction coils, changing about until you find the one that is at fault. It may be, however, that your engine has only one cylinder, or that all the cylinders miss occasionally. ”

“ It was quickly realised that increasing the number of cylinders on an engine was a better way of getting more power than that of increasing the cylinder diameter, as the greater number of cylinders gives better torque—even turning effect—as well as keeping down the weight—this latter because the bigger cylinders must be more stoutly constructed than the small sizes; this fact has led to the construction of engines having as many as eighteen cylinders, arranged in three parallel rows in order to keep the length of crank-shaft within reasonable limits. ”

“ Drying Cylinders.—These cylinders, by the same firm, for which patents were obtained in 1872 and 1887, are made with concave and convex ends, the latter type being shown in Fig. 44. The cylinder body is made [186] of hard cast-iron, turned and polished on outside surface. The ends and trunnions are of tough cast iron, turned to fit into their places, and there secured by bolts and nuts by a patented method, whereby no bolts (excepting for the manhole) are put through the metal, an unbroken surface is preserved, and the annoyance of leakage through the bolt-holes is avoided. ”

“ The heating of the top and bottom of the cylinders, I think, must be particularly important in a short-stroked engine working expansively. In a cylinder of 80 inches diameter and 40 inches stroke, having regard to the time of contact, the area of the bottom will be nearly equal in effect to the surface of the cylinder. ”

“ Tightness of the Cylinder.—The amount of power developed depends principally on the degree of compression to which the explosive mixture is subjected. The economical operation of the engine depends in general upon perfect compression. It is, therefore, necessary to keep those parts in good order upon which the tightness of the cylinder depends. These parts are the piston, the valves, and their joints, and the ignition devices whether they be of the hot-tube or electrical variety. In order to prevent leakage at the piston, the rings should be protected from all wear. ”

“ A metal cylinder grooved with a continuous square-section thread of many turns to the inch was mounted horizontally on a long axle cut at one end with a screw-thread of the same “pitch” as that on the cylinder. The axle, working in upright supports, and furnished with a heavy flywheel to render the rate of revolution fairly uniform, was turned by a handle. Over the grooved cylinder was stretched a thin sheet of tinfoil, and on this rested lightly a steel tracing-point, mounted at the end of a spring and separated from a vibrating diaphragm by a small pad of rubber tubing. ”

“ In all engines the most important parts are the cylinders, which must be well fitted. Boys who have a turning-lathe and the requisite practice in metal-turning can buy rough castings of all the parts of the engine for a few shillings and finish them up themselves. But as only a few of my readers may be so favoured, I will suppose that the cylinders are purchased ready for use. For these cylinders there is a great range in the prices quoted by different firms, the prices varying for the No. 4 cylinder from eight shillings at one firm to twelve shillings and sixpence at another. ”

“ The advantages of this arrangement are that the moving masses are perfectly balanced, the construction of the cylinder is very simple and especially adapted to high pressures, and the reaction of the gases, instead of being directed against a fixed part of the engine, is directed against a moving piston, thus reducing the strain on the structure. ”

“ To overcome the intermittent character of the internal combustion engine a number of cylinders are used, which come into play successively. In the four-cylinder motor one piston is always on the power stroke. ”

“ The area of the half-inch cylinder is nearly two-tenths of a square inch, that of the other nearly eight-tenths. Thus we see that the larger one has four times the area; also the length of stroke is twice as much. According to the rule given above we find the power thus: 2⁄10 × 10 × 1 = 2, and 8⁄10 × 10 × 2 = 16. So that the power of the larger cylinder is precisely eight times that of the small one. In every case it is necessary to allow a certain percentage of the power to overcome friction. The smaller the engine the greater will be the percentage lost in friction. ”

“ However, by increasing the diameter of the screw and making it of such a form that very little or no atmospheric skin friction is encountered, a much better and cheaper engine of a totally different type may be employed. There is no reason why more than four cylinders should be used, but the stroke of the piston and diameter of the cylinder should be increased. ”

“ The way they do this is by running the cylinder the wrong way and holding a piece of stone against them. This gives them a sharp edge. This cylinder is let down so close to the steel plate that there isn't room for the cloth to pass between it and the cylinder without having the face or nap sheared off by the sharp knives of the cylinder that is going round like lightning. That's 'bout all there is to it. Do you get any idea how it works?"
"Oh, yes; I think I see how it is. As the cloth passes over the plate one way, the cylinder whirls the other and clips off the nap. ”

“ Such a model, having a fixed cylinder, has not the friction of other types, and therefore it gives more power, size for size, than an oscillating engine, and does not get so easily out of order.
You must of course have a lathe, which I will therefore suppose you to possess; but should there not be a slide-rest to it, you must get the cylinder bored by a professional turner, for which he will charge about two shillings, according to the size of your castings. ”

“ The motion for working the cylinder, if an independent one, should be rigid and strong; for if there is any spring in it, though the cylinder may be brought in sufficiently close when there is much cutting on the card, if a blank card or one with very little cutting on it comes on, the extra pressure on the needles, especially with a large machine, may prevent it from getting in sufficiently close to clear the hooks from the griffe. ”

“ Our cylinder is to be horizontal, and the steam to work with equal force at each end. The mode by which we obtain (what I take the liberty of terming) a vacuum is, we believe, entirely new; as is also the method of letting the water into it, and throwing it off against the atmosphere without any friction. It is expected that the engine, which is a 12-inch cylinder, will move with a clear force of 11 or 12 cwt., after the frictions are deducted; this force is to act against a wheel of eighteen-inch diameter. ”

“ I made myself comfortable on a grassy slope and proceeded to take the engine down. This I soon discovered was no mean task. It took nearly three hours to remove the cylinders. Woe be unto the man hereafter who puts nuts where they cannot be loosened or places cylinders where they cannot be removed save by an Indian sword-swallower! The result of my investigations was that I found the front piston in fragments, mainly in the bottom of the crank-case. The gudgeon pin was broken in half and the connecting rod was waggling about merrily in the cylinder. ”

“ Increasing the strength in proportion to the square of the diameter soon leads to difficulties, because of the fact that the flow of heat through a metal is a comparatively slow process; the thick walls of the cylinders on large engines cannot conduct the heat away fast enough, and all sorts of strains are set up in the metal, due to the enormous difference in temperature between the inside and the jacket lining of the cylinder. ”

“ In the standard internal combustion engine the cylinder walls are made of cast iron, thick enough to withstand the heavy pressures to which they are subjected should the charge be ignited prematurely. Around them the water circulates under practically no pressure and so the wall of the water jacket is made comparatively thin. Because of the thickness of the cylinder wall the water has to be maintained at a comparatively low temperature so as to keep the interior of the cylinder from growing too hot. ”

“ Engines having more than six cylinders exert a continuous pull as the impulses “overlap,” that is, ignition occurs in one cylinder before another cylinder in the series ends its working stroke. The greater the number of cylinders, the more continuous will be the torque or turning moment. ”

“ The movable cylinder is approximated to the fixed one by means of the iron levers X X, which carry at their ends the weights P, and rest upon wedges M, which may be slidden upon the inclined plane N. These wedges then press the iron bar O, and make it approach the movable cylinder by advancing the plummer-block which supports its axis. When matters are so arranged, should a very large or hard piece present itself to one of the pairs of cylinders, one of the rollers would move away, and let the piece pass without doing injury to the mechanism. ”

“ The cylinder has two movable lids, between which the prayer-roll fits tightly. A handle with an iron rod is passed through the centre of the cylinder and roll, and is kept in its place by means of a knob. A ring, encircling the cylinder, attaches it to a short chain and weight; this serves, when started by a jerk of the hand, to give a rotatory movement, which must, according to rule, be from left to right, and which is kept up indefinitely, the words "Omne mani padme hun," or simply "Mani, mani," being repeated all the time. ”

“ This latter is held between the cylinders, A, which roll it so much the faster in proportion as its diameter is smaller, and by a scraper guide, C, of the same length as the cylinder table, and which may be regulated at will by bolts, c, fixed to the frame, B. The bottom cylinder remains always in the same position, while the axle, D, which carries the intermediate wheels, E, moves about to gear in all the relative positions of the cylinders. ”

“ In setting up a new engine it is obvious that if the flanges of the cylinder are planed parallel with its bore and at the proper distance from its axial line, and the pillow block is made of the proper height, a line stretched axially true with the cylinder bore will pass through the centre of bore of pillow-block brasses, or be equal in height from the engine bed ”

“ A cylinder should be so balanced that it will come to rest at any point. In a rough way a cylinder may be balanced by placing the journals on two carpenter’s squares laid on saw-horses. Gently roll the cylinder back and forth and every time it stops, make a chalk mark on the uppermost bar. If the same bar comes up three times in succession it probably is light, and a wedge should be driven under center band at chalk mark. Continue experimenting until cylinder will come to rest at any point. ”

“ However many cylinders an engine may have, the magneto must be revolved from one point of sparking to the next in the interval between ignition in one cylinder and ignition in the next cylinder to fire. ”

“ A cylinder is generally mounted on its side in a one cylinder engine, and is set up on end when it is desired to use more than one. Therefore, in a one cylinder motor you will notice that the piston moves back and forth, whereas in a two-cylinder, four-cylinder or six-cylinder type, the pistons move up and down. As far as the action of the parts is concerned they work in exactly the same way, only that the valve mechanism has to be changed somewhat.
The cylinder is bolted to a framework called the crank case which furnishes a solid foundation upon which it can rest. ”

“ A cylinder about an inch diameter, and six inches long, exceedingly truly bored, has a solid piston accurately fitted to it, so as to slide easy by the help of some oil; the stem of the piston is guided in the direction of the axis of the cylinder, so that it may not be subject to jam, or cause friction in any part of its motion. ”

“ After the cranks are on their places the keys may be fitted, care being taken that, if the crank last put on had to be moved to adjust it, the sides of the keyways be filed even, otherwise driving the key will tend to move the crank.
Fitting Engine Cylinders. [35] —When engine cylinders are made in quantities, as in locomotive building shops, a great deal of the fitting work is saved by the machine work; but when a single cylinder or a pair of cylinders only are to be fitted up it will not pay to make jigs and appliances; hence, they are usually fitted up entirely by hand. ”

“ Each cylinder with piston and piston-rod weighs no less than 38 tons, while each pair of cylinders with its crank, condenser, and air-pumps, forms in itself a complete and separate engine, and each of the four cylinders is so constructed that it can be, at once, disconnected when required, from the other three, so that the whole forms a combination of four engines, altogether complete in themselves, whether worked together or separately. ”